For a long term evolution LTE (Long Term Evolution) version 8 (Release 8, R8) system, a base station and a user equipment (UE) communicate and transmit data on a carrier. The base station schedules the UE by a physical downlink control channel PDCCH (Physical Downlink Control Channel). The PDCCH may be downlink scheduling grant (DL_grant) or uplink scheduling grant (UL_grant) information, respectively carrying time frequency resource distribution scheduling information and the like for indicating a physical downlink share channel PDSCH (Physical Downlink Shared Channel) or a physical uplink share channel PUSCH (Physical Uplink Shared Channel). The UE, after receiving and decoding the PDCCH, according to the carried scheduling information, receives downlink data PDSCH or sends uplink data PUSCH, and thereafter, the UE feeds back uplink ACK/NACK (AN) for the downlink data, where feeding back ACK indicates determining receiving or receiving success and feeding back NACK indicates that no determining receiving or receiving failure. The base station, after receiving the uplink data, feeds back downlink AN. PDCCH and its scheduled PDSCH or PUSCH, and PDSCH and its corresponding uplink AN have a certain timing relationship, that is, or sequential relationship.
To increase a peak rate and meet the requirement of the future communication system for a data rate, an enhanced long term evolution LTE-A (Long Term Evolution Advanced) system introduces the carrier aggregation CA (Carrier Aggregation) technology, that is, allocating member carriers (Component Carrier, CC) to one UE for supporting a higher rate of data transmission. For example, an LTE version 10 (Release 10, R10) system configures a plurality of carriers for a UE, including a pair of uplink and downlink primary carriers (Primary CC, PCC) and the remaining carriers are secondary carriers (Secondary CC or SCC), where a PCC is also called a primary cell (PCell) and an SCC is also called a secondary cell (SCell), and an uplink AN of the UE can only be sent in an uplink PCell. Additionally, in a carrier aggregation scenario, an LTE R10 system supports cross-carrier scheduling, that is, sending the PDCCH of a plurality of carriers for scheduling a UE to a certain or several carriers, such as a PCell.
In a TDD CA system where a plurality of carriers has different UL-DL configurations, because the UL-DL configuration of a PCell and that of an SCell are different, according to the SCell timing relationship, communication between the base station and the UE through the SCell may be not normally performed.